This invention relates to a four-stroke cycle engine particularly having an improved combustion chamber structure.
In gasoline engines, an engine ready for varying the number of actuating cylinders has been proposed for an object of enhancing a fuel consumption. In the case of four-stroke cycle engine, for example, a construction of the actuating cylinders are all actuated at the time when the engine is on a full load, but two cylinders are only actuated when the engine is on a partial load by cutting ignition of other two cylinders, for example, out of the four cylinders. An arrangement is therefore such that the number of actuating cylinders will properly be adjusted, thereby saving a fuel supply to the engine for enhancing the fuel consumption.
However, in the case of actuating cylinder number variable engine described above, since the cylinders actuated at the time of ignition cutting or reignition change in number, a resultant impact is considerably large, and thus a smooth drive feeling is capable of being spoiled inevitably.